Automatic ignition and control mechanism for oven burners



May 5, 1953 c. M. MAYER ET AL AUTOMATIC IGNITION AND CONTROL MECHANISM FOR OVEN BURNERS 3 Sheets-Sheet 1 Filed Dec. 10, 1951 INVENTORS (haw/es M. Mayer BY iiJohn/Z Hoff IDN I1 IT May 5, 1953 C. M. MAYER ET AL AUTOMATIC IGNITION AND CONTROL MECHANISM FOR OVEN BURNERS Filed Dec. 10, 1951 50: I 48 I I 39 i 3 Sheets-Sheet 2 INVENTORS Char/es M Mayer BYfi 706/7 M Hoff /im m Fflys.

May 5, 1953 c. M. MAYER ET AL 2,637,387

AUTOMATIC IGNITION AND CONTROL MECHANISM FOR OVEN BURNERS Filed Dec. 10, 1951 3 Sheets-Sheet 3 /b/ I a f INVENTORS' (/zar/es M Mayer L BY 9.10m? M, Hoff Patented May 5, 1953 UNITED STATES PATENT QF AUTDMATIO- IGNITION AND CONTROL MEGHANISM FOR OVEN BURNERS laims 1 This invention relates to. an; automatic eleetrig. ig'ntion and control mechanism for cooking; range burners using gaseous fuel. enti ies amodification of the control mechanism shown in the co -pending application of Charles M. Mayer and Johny; Hoff filed April 3, 1950, Serial N0, llfia fitl i, 119W Eatent No. z'fiia'i 'lilil. It is especially designed and adapted for automatically igniting and eon: trolling the operationot oven. burners in cooking ranges, and maybe used; conjunction with a time control mechanism. or independently thereof; as desired.

The mechanism is designed for use with a main gaseous fuel burnerwhiehis adapted (1- b? nite by a gaseous fuel pilot. burner, As long as the pilot hut-neris ignited. it is immaterial whether or not the main burner, burns, constantly, It may be extinguished iotsome reason, but it will be promptl' reeignited by the pilot Tour-her it fuel is supplied thereto. But, if; the pilot burner is extinguished for any reason while the m inc ntrol valve is still Open to supply gas to burner a very dangerous situation sorneti arises. Let us assume that both the pilot lqu andv h in. ur r are; xtin uis ed durin operation Jim-somev reason. (it Gail then flow to the main burner but since the pilot outer is extinguished the main burner will not be ignited and unburned will; accumulate the oven Whieh violently explode when an attempt is made to ignite either the main or pilot r; It; hasbeen found by experience thatbot the pilot hurnet and, then-lain burner are f et quen y extinguished clurii g operation, Th s is some:v tines clue to. amomentary failure of-the gas so pla er the slamming of the ov n, .dq i' 11 to vetother e ons.

in Greer to etevent any a cuinulation o m: tome-d as ens thus e iminate d n er of an v e fl i hem-rote im event th l t ns, ita ion! a safety mainle be 1?: see. e ent th le? is- 1' luring ope tlon.

pai atu js is so censt uoted anti arranges tn 2 2 lso ut lise his Sa ety etr l va v m tha ism w l ie lls-gas t. and a o n tiat its ate se atiee w? th m mt'a d ih minate il manually operables'hut off 1 Q1??l+1. i il burns? centre; aaper ti seii awesil? si e a th s see ti fil' etwtith the iv-es a iii i t e a ur A n rma ly pen ma ts;

" element and the solenoid. Assoon as'tl e, s

n er-r n n con u t e w en theses. s11 u manifold; and the burners. During, oper tion gas flows from the manifold into a safety, cont val e mechanism, F the saf ty 9 21 1 V? e m c i m fl w t rough at 2 1 breath ond directly be e ilot burner: a le hl tu h the main conduit, and a stand arli' thermost 1L- all r d n em e ture cqnt ql valve to Pv id to ni i te o e a n f sih the, il burn and we a n umen e- 19s s fthe ma ter c w t h e eizes wr ught 11 7? a ly closed he mostatica l operat s sw h, n e st i resi a e, ignition el ment an a. so e4 noid which is, operatively conneeted to the safety on ve m i-c e i m- The ene iza ie the solenoiol causes it to operatehthe saiety con: 7- valve m q sm m n r'm t he flow of as to the ilo n r W i e utt iis o he ,9 Q g s to the ma n bu n The Pil t tu s is igni ed by the lee t n ment and. p ieti a ame ains a therm s atic e em. .i. which controls the operation oi the normally closed, switch, and against a tl er 'nocoupl e wh h is 'e a ve y con eis h a iety t n e v lv msshtn sm- After h rm tat s e wen e se ed, it ens h iermell ee switch which (fie-ener izes the electric 'ig trol switel having two closed positions is aci is rerisrs z ri he sa et c n e m h ew s e itqm'ai l e ated by r n means t u p s o e mai burnerlirte eh'tte. ms n eon dl al nd h n empe ature cane r l val ehe ma ur e s hen s'ri teit the 'l ur i hsthe inqsql a s 101 2 it is ie te l by the pi o b rner meintein the see cqntr a v me hani m n 1 t. is See It n burner and'the pilot hurrier.

lates the, supply of gas to the main burner so as o meimain the s iiei ven t x il 1011s a he Pi t bur e s gn ed heme; will burn normally under the control of t temperature control valve. But ifduipin ope etiqn the il t ur s; s sxtineui rsese he helmewup e w l i m and llo e, saf t @Q tml ta e e b 1 to automatically cut of; the of.

the main burner and the pilot burner. As an example of the manner of operation of the apparatus, let us assume that during operation the pilot burner is suddenly extinguished, for instance, by a momentary failure of the gas supply from the manifold to the burners. The thermocouple immediately cools, allowing the safety control valve mechanism to cut off communication between the manifold and both the main burner and the pilot burner. Then after the thermostatic element has cooled, closing the normally closed switch, which is maintained open by the thermostatic element during normal operation of the oven, the electric ignition element and the solenoid are again energized since the master control switch is still closed. The energization of the solenoid will cause it to operate the safety control valve mechanism to establish communication between the manifold and the pilot=burner only. Then when gas is again ava lable the pilot burner will be ignited and reestablish normal operation of the oven as previously described. In the event of a power failure during normal operation of the oven, the main burner will continue to operate normally under the control of the oven temperature regulator valve until the operation of the burner is terminated, assuming of course that the pilot burner continues to burn. In the event of a power failure before gas is turned on to initiate operation, the pilot burner can be manually ignited as will be hereinafter explained. The supply of gas to both the main burner and the pilot burner will then be controlled by the pilot burner through the thermocouple and safety control valve mechanism as previously described.

In order to extinguish the pilot burner and the main burner to terminate operation we provide an interrupter switch in the circuit between the thermocouple and the safety control valve mechanism. This switch is located in the same casing as the master control switch and is opened and closed in unison with the opening and closing of the master control switch. Then when the interrupter switch is opened the circuit between the thermocouple and the safety control valve mechanism is broken which permits the safety control valve mechanism to cut off the supply of gas to both the pilot burner and the main burner and thus terminate operation.

When it is desired to use the apparatus in conjunction with any standard time control mechanism, we provide a supplemental master switch and a supplemental interrupter switch which are simultaneously opened and closed at predetermined times by the time control mechanism. The supplemental master switch is inserted in the main circuit controlled by the primary master switch, and the supplemental interrupter switch is inserted in the thermocouple circuit controlled by the primary interrupter switch. In use the time control mechanism is set to initiate operation of the oven burner at a predetermined time and to terminate operation thereof at a predetermined later time, after the master control switch and the interrupter switch have been set for automatic operation. Then when the supplemental switches which are now in series with the primary switches are closed by the time control mechanism the apparatus will function in the same manner as previously described.

The principal object of the invention is to provide an improved electrical ignition and automatic control system for cooking range oven burners using gaseous fuel.

Another object of the invention is to provide in an electrical ignition and control system of the character described improved means for completely shutting off the supply of gas to both the main burner and the pilot burner in the event the pilot burner becomes extinguished for any reason during operation.

Another object of the invention is to eliminate all manually operable shut off valves in a control system of the character described.

Still another object of the invention is to provide an improved electrical ignition and control system of the character described which may be used in conjunction with a time control mechanism or independently thereof as desired.

Other and more limited objects of the invention will be apparent from the following specification and the accompanying drawin forming a part thereof, wherein:

Fig. 1 is a diagrammatic View illustrating our improved electrical ignition and safety control mechanism as applied to a cooking range oven burner using gaseous fuel;

Fig. 2 is an enlarged central vertical section through the safety control valve mechanism showing the various parts in position to cut off the supply of fuel to both the pilot burner and the main burner;

Fig. 3 is a view similar to Fig. 2 showin the various parts in the position they are automatically moved to when the master control switch is closed to initiate the operation of the main oven burner; and

Fig. 4 is a wiring diagram showing the switches and the main control valve in off position.

Referring now to the drawings by reference characters, the numeral I indicates a gaseous fuel burner which is mounted in or in heating relation to a cooking range oven 2. Gaseous fuel is supplied to the burner I from a manifold M through a conduit 3. Interposed in the conduit 3 are a safety control valve mechanism generally indicated by the numeral 4, and an oven temperature control valve 5. During operation gas flows from the manifold M through the conduit 3 to the safety control valve mechanism 4, to be described in detail hereinafter. From the safety control valve mechanism 4 the gas flows through the conduit 3 and the oven temperature control valve 5 to the burner I. The oven temperature control valve 5 is operative to regulate the amount of gas flowing to the burner I in order to maintain the oven at any desired set temperature. The valve 5 is set to any desired temperature by a handle I I having a pointer I2 which cooperates With a graduated dial I3 carried by the valve 5. The valve 5 is, controlled according to the temperature setting by a thermostatic element I4 which is mounted in the oven 2 and is connected to the valve 5 as shown at I5. The oven temperature control valve 5 is of standard well known construction. Consequently it is not shown in detail herein. There are many different constructions available any one of which will work equally well herein. Gas is also supplied to a pilot burner I6 through a branch conduit I! which extends between the safety control valve mechanism 4 and the pilot burner I6. The pilot burner I6 is disposed adjacent the rear end of the main burner I in position to ignite the burner I when gas is supplied thereto. An electrical ignition element I8 is operatively associated with the pilot burner I6 in position to ignite the pilot burner I6 when gas is supplied thereto. A thermostatic element I9 and a multiple thermoaccess? couple 28; are mounted in position to be heatedby a fiame from the pilot burner. The thermostatic element to is operative to open and closea switch H which controls the energization of the electrical ignition element lit and a solenoid 22- which when energized operates the safety control valve mechanism to supply gas to the pilot burner It only as will; be described in connection with the description of the safety control valve mechanism and the operation of the whole apparatus. The thermocouple Ell when heated is operative to hold the safety control valvemechanism in condition to maintain the supply of gas to both the pilot burner it and the main burner I,

as will also be described inconnection with the 1 description of the safety controlvalve mechanism and the operation of the apparatus.

A master control switch 23 is provided to initiate operation of the burner I, and an interrupter switch it is provided to terminate operation thereof. The switches 23 and 2-4 each have two closed posit-ions and are mounted in a case 25 secured to an accessible part 65 of therange body and are opened and closed in unison by a switch stem d and a switch handle 8.

An electric circuit-between the thermocouple and the safety control valvemechanism- 5 is established by a copper tube 26 which encloses-an insulated wire 21. The wire'2'lis severed between the thermocouple Zlland the safety control mechanism 4 and an interrupter 28 having terminals and 3B is interposed between thesevered ends. One of the severed ends of the wire 21 is connected to the terminal 29- and the other severed end is connected to the terminal 39. The purpose of the interrupter 28' will be explained in-detail in connection with the description of the operation of the apparatus.

The construction of the safety control valve mechanism 4 and its connection to the solenoid 2-2 will now be described reference being had to Figs. 2 and 3 of the drawing. This mechanism comprises a casing having a chamber 35 in oneend thereof and a chamber 31 in the other end thereof. The chambers 3t and 31 are connected by a bore 38 of reduced diameter. A valve seat39is located at one end of the bore 38 and a similar valve seat 48 is located at the other end of the bore 33. The chamber 36 is closed bya removable cap M and the chamber N is closed by a removable cap it. A sleeve 33, having end walls-M and 45, is carried by the cap M and extends into the chamber 35. mounted in a bushing M carriedby the end wall of the sleeve 43, extends from the chamber 36 into the sleeve 43. A valve disc itof suitable material is secured to one end of the valve stem 48 within the chamber 35, and-a metal disc 49 is secured to the other end of the stem 46 within the sleeve 43. A spring 56dispcsed' about the valve stem 46' between the valve disc is and the end wall d5 of the sleeve i3 normally holds the valve disc 48 against the valve seat 39. A horseshoe magnet 5| is secured to one end of a hollow exteriorly threaded stud 52 which extends out through aligned apertures in the end wall 44,, of the sleeve t3, and in the end of the cap M. A nut 53} screwed onto the outer portion of the stud 52 securely holds the magnet 51 and the sleeve 43in place. The legs ofthe magnet 5| have a winding 5t thereon one end of which is connected to the tube. .23 and they other end oiwhich' is connected to the wire 27 in the tube 26, The tube 26 is inserted into the hollow stud, 52 andis held in place by a screw fitting 520.. A sleeve 55 is screwed into A valve stem it which is slid-ably 6 athreaded recess in'the end cfithe cap-42; as in dicated at 56, and extendsinto the chamber 31' a slight distance. One end'ofthe sleeve 55 is closed by an end wall 51, and the other end which is open registers with a circular aperture 58- in the end wall-ofthe cap it. A plug 55 is slidablymounted in: the sleeve 55 and extends out throug h the aperture 53 in the cap 42; A stem 62 which is secured to the inner end of the plug 59 extends i out through an aperture 63, in the end wall 51 of the sleeve-'55, and through the chamber 31 and into the bore 38. The stem 62 has a collar 64 rigidly secured thereon between the end. wall 51 and; the outer end of the stem. A valve disc 65 of suitable material is slidablymounted upon the stem 62 between the end wall 51 of the sleeve 55 and the collar 64. The valve disc 65 is adapted to engage the valve seat 40 to cut off the flow of gas into the chamber 32 during the initiation of operation as will be hereinafterdescribed. A compression spring 66 disposed about the stem 62 between the end wall 51' and the valve disc normally yieldingly holds the valve disc 65 against thecollar M. A compression spring 6'! which is stronger than the spring 66 is disposed about the stem 62 within the sleeve55 between the inner face of the end wall 5'! and the inner end of the lug 59*. The spring is operative to return the plug 59, stem 82 and valve disc 65 from the position shown in Fig. 3 back to their normal position as shown in Fig. 2, against the resistance of the spring lit. A port 68 in the casing 35 provides communication between the chamber 36 and the conduit 3 to allow gas to fiow'from the manifold through the conduit 3 into the chambertt. During normal operation of the main burner l gas flows from the chamber 35 through the re duced intermediate bore Stand into the chamber 3']. A port 8% which establishes communication between the conduit I! and the bore SB-isprovided to supply gas to the pilot burner it; and a port BE! establishes communication between the chamber 3'! andthe conduit 3 to permit the flow of gas from the chamber 31 to the main burner Ithroughthe main control valve, and the oven temperature control valve.

The solenoid 22 may be connected to the safety control valve mechanism t in any desired suitable manner. As shown herein it is secured to the cap ti? Of the safety control valve mechanism with armature thereof connected. directly to the plunger 59 vof the safety control valve mechanism.

The master control switch 23 comprises the arm .15 which is. connected to the stem I for rotation therewith, and the two contacts it and l? which are spaced 18' apart and are adapted to be selectively engaged by the arm '55 when it is rotated in either direction from its normal 01f position. The interrupter switch 2% comprises the arm it, which is also connected to the valve stem '1 for rotation therewith, and the two contacts 19 and 88 which are adapted to be selectively engaged by the arm it.

In order that the operation of the burner I may be automatically initiated at a predetermined set time and terminated at a predetermined set later time, we provide-a supplemental master switch a supplemental interrupter switch it and a standard time control mechanism 84 which includes a selfestarting electric clock 85 and is operative to open and closethe supplemental switches 32 and 83 at predetermined set times. For manual control the valve stem 1 of the switches-23 and 24 is turned'inaclockwise direction and for automatic control it is turned in a counterclockwise direction.

The supplemental master switch 82 comprises the contacts 93 and 94 which are adapted to bebridged by a conductor bar 95; and the supp1emental interrupter switch 83 comprises the contacts 91 and 98 which are adapted to be bridged by a conductor bar 99. The conductor bars 95 and 99 are adapted to be moved toward and away from the contacts 93, 94, 97 and 98 at predetermined times by the time control mechanism 84 through a connecting link I99.

The operation of the apparatus will now be described in connection with Fig. 4. For manual control of the burner I the stem I is rotated in a clockwise direction 99 by the handle 8, which moves the interrupter switch 24 and the main control valve from their normal ofi positions as shown in Fig. 4 to the switch arm I5 into engagement with contact I6 and the switch arm I8 into engagement with the contact 19. Current will now flow from one side I9I of the line through the lead I92, switch arm I5, contact I6 and lead I93 to the normally closed thermally opened switch 2|. From the switch 2| the current flows through the lead I94 to the solenoid 22 and from there back to the other side I95 of the line through the lead I96. Current also flows from the switch 2| through the leads I 94 and I9! to the electric ignition element I8 and from there back to the side I95 of the line through the leads I98 and I96. The solenoid 22 and the ignition element I8 are now energized. The solenoid 22 being energized shifts the various parts of the safety control valve mechanism from the positions shown in Fig. 2 to the position shown in Fig. 3. Gas can now flow to the pilot burner I6 where it is ignited by the ignition element I8, but it cannot yet flow to the main burner I since the valve mechanism in the chamber 31 of the safety control valve mechanism is maintaining the entrance thereto closed. The pilot burner being ignited heats the thermocouple 29 and the thermal element I9. The thermocouple being heated generates a minute current of the order of 200 to 259 millivolts which flows from the thermocouple through the tube 29 to the winding 54 of the electromagnet 5| and from there through the wire 2'I' to the terminal 39 of the interrupter 28. From the terminal 39 the current flows through the lead I99, contact I9, switch arm 18 and lead II9 to the terminal 29 of the interrupter 28, and from there back to the thermocouple 29 through the wire 21. The thermocouple current energizes the electromagnet 5| sufficiently for it to hold the valve mechanism in the chamber 36 in the position shown in Fig. 3 after it has been moved to this position by the solenoid 22, but not enough for the electromagnet to attract the mechanism from the position shown in Fig. 2 to the position shown in Fig. 3. The heating of the thermal element I9 causes it to open the normally closed switch 2| which breaks the circuit to and deenergizes the solenoid 22 and the ignition element I8. As soon as the solenoid 22 is deenergized the spring 6I' returns the valve mechanism in the chamber 31 back from the position shown in Fig. 3 to the position shown in Fig. 2 while the electromagnet 5| holds the mechanism in the chamber 36 in the position shown in Fig. 3. Gas can now fiow to the main burner I where it is ignited by the pilot burner I6. Under normal conditions the burner I will now operate under control of the oven temperature control valve 5 until its operation is terminated by the opening of the switches 23 and 24. The opening of the interrupter switch 24 breaks the thermocouple circuit and deenergizes the electromagnet 5| after which the spring 59 returns the mechanism in the chamber 36 from the position shown in Fig. 3 to the position shown in Fig. 2, thus cutting off the supply of gas to both the main burner and the pilot burner. If the pilot burner is extinguished for any reason during operation then the thermocouple 29 and the thermal element I9 will cool. The electromagnet 5| will then be deenergized and release the mechanism in the chamber 36 which will then be returned by the spring 59 to the position shown in Fig. 2 cutting off the supply of gas to both the pilot burner I6 and the main burner I. When the thermal element I9 cools, which is after the thermocouple has cooled, the switch 2| will close. The apparatus will then recycle as described as soon as gas is available.

For automatic control of the main burner I the stem I is rotated through in a counter-clockwise direction which brings the arm I5 of the master control switch 23 into engagement with the contact I! and the arm I8 of the interrupter switch 24 into engagement with the contact 89; and the time control mechanism 84 is set to close the supplemental switches 82 and 83 at the desired time and to reopen them at the desired later time. The switches 23 and 82 in the main circuit are now in series with each other, and the switches 24 and 83 in the thermocouple circuit are also in series with each other. When the time control mechanism 84 closes the supplemental switches 82 and 83 current will flow from the side I9I of the line through the lead I92, switch arm I5, contact 11, lead III, switch 82 and leads H2 and I93 to the normally closed switch 2|. From the switch 2| the current will flow through the solenoid 22 and the ignition element I9 and back to the other side I95 of the line. In the thermocouple circuit current will flow through the tube 26, winding 54 and wire 21 to the terminal 39. From the terminal 39 the current will flow through the leads I99 and I I3, switch 83, lead I I4, contact 89, switch arm I8 and lead I I9 to the terminal 29 and from there through the wire 2! back to the thermocouple 29. The apparatus will now function as described in connection with manual control until the time control mechanism opens the switches 82 and 83 which breaks the main and the thermocouple circuits, thus terminating operation as previously described.

From the foregoing it will be seen that we have provided an automatic ignition and control apparatus for gaseous fuel oven burners in which all manually operable shut off valves in the fuel supply conduit have been eliminated and that we use the automatically actuated safety control valve mechanism 4 both as a safety control valve during operation and as a cut off valve when the burner I is not being used. It will also be seen that the operation of the apparatus is primarily under the control of the master control switch 23 and the interrupter switch 24 which are opened and closed in unison with each other. The closing of these switches initiates operation of the burner I and the opening of these switches terminates operation thereof. During operation the apparatus is automatically controlled by the pilot burner I6 and the safety control valve mechanism 4. If during operation the pilot burner I6 is extinguished for any reason the safety control valve mechanism 4 will promptly out ofi the supply of gas to both the pilot burner I8 and the main burner I, and will maintain it cut off to burner, an electric circuit between said thermocouple and said electromagnet through which said magnet is energized by said thermocouple when said thermocouple is heated, an interrupter switch having two closed positions interposed in said circuit and operative to open and close said circuit and thereby control the energization of said electromagnet, a normally open master switch which is operative when closed to energize said solenoid and said electric ignition element, a normally closed switch disposed in series with said master switch which is operative when opened to deenergize said solenoid and said electric ignition element, a thermostatic element adapted to be heated by said pilot burner and operative when heated to maintain said normally closed switch open and when cool to maintain said normally closed switch closed, a supplemental master switch disposed in series with said master switch and said normally closed switch, a supplemental interrupter switch interposed in said circuit in series with said interrupter switch when said interrupter switch is in one of its closed positions, and a time control mechanism operative to simultaneously close and open said supplemental master switch and said supplemental interrupter switch at predetermined set times.

6. An automatic ignition and control apparatus as defined in claim in which said master control switch and said interrupter switch are connected together to be opened and closed in unison with each other.

'7. In an automatic ignition and control apparatus of the character described the combination of a main burner, a pilot burner operative to ignite said main burner, an electric ignition element operative when energized to ignite said pilot burner, a gaseous fuel supply manifold, a main conduit through which fuel is supplied to said main burner from said mainfold, a safety control valve mechanism operative to cut off the supply of fuel to said main burner and said pilot burner interposed in said conduit between said main burner and said manifold, a secondary conduit extending between said safety control valve mechanism and said pilot burner through which fuel is supplied to said pilot burner, a solenoid operatively connected to said safety control valve mechanism, said solenoid being operative upon energization to first set said safety control valve mechanism in condition to supply fuel to said pilot burner while cutting off the supply of fuel to said main burner and upon subsequent deenergization to set said safety control valve mechanism in condition to also supply fuel to said main burner, an electromagnet associated with said safety cOntlOl valve mechanism and operative when energized to maintain said safety control valve in said last set condition, a thermocouple adapted to be heated by said pilot burner, an electric circuit between said thermocouple and said electromagnet through which said magnet is energized by said thermocouple when said thermocouple is heated, an interrupter switch interposed in said circuit and operative to open and close said circuit and thereby control the energization of said electromagnet, a normally open master switch which is operative when closed to energize said solenoid and said electric ignition element, a normally closed switch disposed in series with said master switch which is operative when opened to deenergize said solenoid and said electric ignition element, and means responsive to said pilot burner and oper- 12 ative to maintain said normally closed switch open while said pilot burner is ignited.

8. An automatic ignition and control apparatus as defined in claim 7 in which said master control switch and said interrupter switch are connected together to be opened and closed in unison with each other.

9. In an automatic ignition and control apparatus of the character described the combination of a main burner, a pilot burner operative to ignite said main burner, an electric ignition element operative when energized to ignite said pilot burner, a gaseous fuel supply manifold, a main conduit through which fuel is supplied to said main burner from said manifold, a safety control valve mechanism operative to cut off the supply of fuel to said main burner and said pilot burner interposed in said conduit between said main burner control valve and said manifold, a secondary conduit extending between said safety control valve mechanism and said pilot burner through which fuel is supplied to said pilot burner, a solenoid operatively connected to said safety control valve mechanism, said solenoid being operative upon energization to first set said safety control valve mechanism in condition to supply fuel to said pilot burner while cutting oil the supply of fuel to said main burner and upon subsequent deenergization to set said safety control valve mechanism in condition to also supply fuel to said main burner, an electromagnet associated with said safety control valve mechanism and operative when energized to maintain said safety control valve in said last set condition, a thermocouple adapted to be heated by said pilot burner, an electric circuit between said thermocouple and said electromagnet through which said magnet is energized by said thermocouple when said thermocouple is heated, an interrupter switch having two closed positions interposed in said circuit and operative to open and close said circuit and thereby control the energization of said electromagnet, a normally open master switch having two closed positions which is operative when closed to energize said solenoid and said electric ignition element, a normally closed switch disposed in series with said master switch WhlCh is operative when opened to deenergize said solenoid and said electric ignition element, means responsive to said pilot burner and operative to maintain said normally closed switch open while said pilot burner is ignited, a supplemental master switch disposed in series with said master switch and said normally closed switch, a supplemental master switch disposed in series with said master switch and said normally closed switch when said master switch is in one of its closed positions, a supplemental interrupter switch interposed in said circuit in serie with said interrupter switch when said interrupter switch is in one of its closed positions, and a time control mechanism operative to simultaneously close and open said supplemental master switch and said supplemental interrupter switch at predetermined set times.

10. An automatic ignition and control apparatus as defined in claim 9 in which said master control switch and said interrupter switch are connected together to be opened and closed in unison with each other.

11. In an automatic ignition and control apparatus of the character described the combination of a main burner, a pilot burner operative to ignite said main burner, an electric ignition element operative when energized to ignite said pilot burner, a gaseous fuel supply manifold, a main conduit through which fuel is supplied to said main burner from said manifold, a safety control valve mechanism operative to cut off the supply of fuel to said main burner and said pilot burner interposed in said conduit between said main burner control valve and said manifold, a secondary conduit extending between said safety control valve mechanism and said pilot burner through which fuel is supplied to said pilot burner, a solenoid operatively connected to said safety control valve mechanism, said solenoid. being operative upon energization to first set said safety control valve mechanism in condition to supply fuel to said pilot burner while cutting off the supply of fuel to said main burner and upon subsequent deenergization to set said safety control valve mechanism in condition to also supply fuel to said main burner, an electromagnet associated with said safety control valve mechanism and operative when energized to maintain said safety control valve in said last set condition, a thermocouple adapted to be heated by said pilot burner, an electric circuit between said thermocouple and said electromagnet through which said magnet is energized by said thermocouple when said thermocouple is heated, an interrupter switch having two closed positions interposed in said circuit and operative to open and close said circuit and thereby control the energization of said electromagnet, a normally open master switch which is operative when closed to energize said solenoid and said electric ignition element, a normally closed switch disposed in series with said master switch which is operative when opened to deenergize said solenoid. and said electric ignitiOn element, means responsive to said pilot burner and operative to maintain said normally closed switch open while said pilot burner is ignited, a supplemental master switch disposed in series with said master switch and said normally closed switch, a supplemental interrupter switch interposed in said circuit in series with said interrupter switch when said interrupter switch is in one of its closed positions, and a time control mechanism operative to simultaneously close and open said supplemental master switch and said supplemental interrupter switch at predetermined set times.

12. An automatic ignition and control apparatus as defined in claim 11 in which said master control switch and said interrupter switch are connected together to be opened and closed in unison with each other.

CHARLES M. MAYER. JOHN M. I-IOFF.

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